Aturus natangensis Protz, 1900

Gerecke, Reinhard, 2014, Studies on European species of the water mite family Aturidae Thor (Acari: Hydrachnidia), Zootaxa 3841 (1), pp. 1-46 : 13-14

Aturus natangensis Protz, 1900

Fig. 8

Aturus lelgioensis Rensburg, 1971 , nov. syn.

Material examined. Type series: Paratype ♀ SMF 42861, " Aturus natangensis Protz ♀ Co-Type Ost-Preußen, Kellermühler Fließ b. Tapiau, 8.1900, Protz leg. 1450" (1 ♀ dissected and strongly damaged).

Germany: SMF 49822, " Aturus natangensis Protz ♂ Schwabach oberhalb Uttenreuth, Erlangen, H.-J. Stammer leg. 2.7.1949 798" (2 dissected ♂♂); SMF 49846, " Aturus natangensis Protz ♂. Herzogenaurach bei Erlangen; i. d. Aurach. H.-J.- Stammer leg. 23.9.1949 941" (5 ♂♂, 4 dissected, mounting medium with air intrusions); Russia: SMF 42857, " Aturus natangensis Protz ♀. Original-Fundort. Ost-Preußen, Kellermühle bei Tapiau, 9.1900, Protz leg. 1440" (2 ♀♀ dissected); from type locality; SMF 42856, " Aturus natangensis Protz ♂ Original-Fundort Ost- Preußen, Kellermühle bei Tapiau, 9.1900, Protz leg. 1439" (4 ♂♂, two dissected, one of them partly under lacquer, two undissected, one dorsal, one ventral); SMF 42918/19, same site and date, without species identification: 42918 ♂, 42919 3 ♀♀; SMF 49856, " Aturus natangensis Protz ♂ Ostpreußen, Grünwehr, Protz leg. 6.10.1902 [aus Viets Prp. 1447] 5278" (2 dissected ♂♂).

Aturus lelgioensis , type series: Holotype ♂, NHMB 4559 " Aturus lelgioensis spec. nov. Type specimen ♂ Präp. 142 29.9.1968 Lelgio 12°C Coll. 5" (dissected, dried, squeezed); paratypes: same site and date NHMB 4560- 4564, 2 ♂♂, 2 ♀♀ (incl. "allotype" on two slides, idiosoma/palps, 4560/61, all dried and squeezed).

Remarks. Males of A. natangensis are characterized by Dgl-3–5 (setae relatively short, Dgl-3 deeply bifurcated, Dgl-4–5 simple) on each side close to each other in an obtuse triangle (distance Dgl-4> Dgl-3/5), located on elevated areas flanking a shallow medial depression; in the posterior area of fusion between dorsal and ventral shield a few scattered short setae. Lgl in the dorsal furrow, Lgl-1–3 separated, Lgl-3 close to Lgl-4 (setae Lgl-1–2 as long as Dgl-setae, Lgl-1 fine, simple, Lgl-2 stronger, bifurcated; Lgl-3–4 very fine, short and hair-like). Posterolaterally, a narrow strip of upwardly-bent ventral shield with stronger, posteriorly-directed setae in a line all over the posterior idiosoma margin; without bulbous setae. III-L-5 with a slightly thickened seta proximally on posterior surface, a thickened, whip-like seta posteriorly at distal margin, and a row of about 8 distoventral setae. IV-L-4 with convexly protruding ventral margin, distally a pair of strong enlarged distal sword setae and about 8 strong but simple setae. IV-L-5 curved, 4–5 strong proximal blade setae, 4–5 ventral line setae in proximal half, distal setae simple, various in length. Females found with A. natangensis males bear about 10 pairs of Ac in a single line, Vgl in area of secondary sclerotization, distanced from primary sclerotization border, Dgl-4 relatively close to Dgl-5 (distance ratio Dgl-3–4/4–5> 2.5); and the medial 2–3 acetabula separated from the remaining by an enlarged small interspace.

Notwithstanding the bad state of the type series of Aturus lelgioensis , it is possible to state that all diagnostic characters defined by Rensburg (1971) are not suitable for separating the species from A. natangensis : (1) No remarkable differences are found in number and density of posterior idiosoma setae. (2) As documented by the two specimens in SMF 49856, the position of Ac ventrocaudally flanking the gonopore is variable: One specimen agrees with the original description given for A. natangensis , having two Ac rather close to each other in ventrocaudal position, in the other one, the situation is as given for A. lelgioensis , with one Ac shifted rather far to the ventral surface, the other one in a transitional position. Study of the other specimens of A. natangensis produces intermediate situations. (3) The proportions of IV-L-4 measured in A. natangensis are rather various (L/H ratio 1.4–1.9). As the specimens are obviously not squeezed, the observed range is probably best explained by the influence of the relative position of the segment. It is obviously slightly flattened and can rotate against the preceding segment, resulting in diversity of observed proportions depending on view angle. Segment IV-L-4 is not more slender in A. lelgioensis , the proportions are within the range of A. natangensis . (4) An arrangement of Ac "on separate levels" cannot be observed in the types of A. lelgioensis – they lie in a single line as in A. natangensis . However, the finding of exceptional Ac placed lateral from the main line is well possible in Aturus species and cannot be a basis for introducing new taxa. Aturus lelgioensis is therefore a junior synonym of A. natangensis .

Figures

FIGURE 8. Aturus natangensis, male dorsum. Scale bar = 100 µm.